Broad-band erbium-doped fiber amplifier with double-passconfiguration

We demonstrate a broad-band silica-based erbium-doped fiber amplifier (EDFA) with double-pass configuration. The signal gain and noise figure are obtained more than 24 dB and less than 6 dB, respectively, for 1526-1562 nm and 1569-1605 nm. The same signal gain can be achieved with 53% less pump power and 45% shorter erbium-doped fiber length, compared to a conventional parallel type EDFA. Furthermore, the noise figure and power conversion efficiency are improved for the wavelength range     

Passivity-based Nonlinear Control for a Ballbot to Balance and Transfer

International Journal of Control, Automation and Systems - Ballbot is a robot that can transfer to a given position while maintaining a self-balanced upright posture on a spherical ball. This paper...     

A novel modified analytical method and finite element method for vibration analysis of cable-driven parallel robots

Journal of Mechanical Science and Technology - Cable-driven parallel robots (CDPRs) are vulnerable to vibration due to the inevitable flexible properties of the cables. Thus, vibration analysis is...     

Control system design for the mock ventricle with aortic and mitral valve resistance uncertainty

Reproducing the native left ventricle’s contractile behavior is the key ingredient for the mock cardiovascular circulatory system. It can be achieved by controlling either mock ventricle’s pressure or volume so that it could follow the reference signal calculated by the Elastance waveform. However, due to inherent uncertainties of the parameter values of the mock ventricle, such as check valve resistance, it is difficult to achieve high quality control performance. In this paper, we present an adaptive control scheme to overcome this parameter value uncertainty and to achieve high quality control performance. To the best knowledge of the author, it is the first report that reproduces the mock ventricle pumping dynamics precisely considering the resistance of the aortic/mitral check valves and overcoming the uncertainty of them. In the paper, along with the detailed design of the controller, rigorous proof of the stability and the convergence is presented as well. Computer simulation was performed using an electrical-analog cardiovascular circulatory system model and a piston pump mock ventricle model. Results confirmed that adaptive control achieved almost perfect tracking performance in spite of large parameter uncertainty and high bandwidth dynamic characteristics of the mock ventricle. Performance comparison verified the superiority of the adaptive controller over PID controllers.